Wright said that Borneo's lowland forests are primarily cleared for oil palm plantations. In the mountains the rain forests are rich in coal seams, and several mining companies already hold access rights.

Many of the species were discovered in an 85,000-square-mile (220,000-square-kilometer) mountain rain forest in a central region of the island that conservationists call the Heart of Borneo.

The region is increasingly pressured by human development, so WWF is working with local officials in Indonesia, Malaysia, and Brunei to develop a series of protected areas and sustainably managed forests.

Stuart Chapman, international coordinator WWF's Heart of Borneo Program, said in a media statement: "The remote and inaccessible forests in the Heart of Borneo are one of the world's final frontiers for science."